1. Field of the Invention
The present invention relates generally to a home network, and more particularly, to a method and system for providing input in a home network using Universal Plug and Play (UPnP), a home network middleware protocol.
2. Description of the Related Art
In general, a home network, which consists of Internet Protocol (IP)-based private networks, connects all types of various devices used in a home, such as Personal Computers (PCs), intelligent products and wireless devices, to one network through a common virtual computing environment called ‘middleware’, and controls the devices.
The term “middleware” refers to software for connecting various digital devices on a peer-to-peer basis and enabling communication between the devices. Various technologies, such as Home AV Interoperability (HAVI), Universal Plug and Play (UPnP) control device, Java Intelligent Network Infra-structure (Jini), and Home Wide Web (HWW), have been proposed as middleware.
Since the addition of a Plug and Play (PnP) function to the operating system, it has been very easy to install and set peripheral devices of PCs. UPnP, which has evolved from PnP, is a technology for enabling various home appliances and network devices such as network printers and Internet gates to perform networking, especially home networking, by extending such convenient functions to the entire network based on Internet standard technologies such as Transmission Control Protocol/Internet Protocol (TCP/IP), Hyper Text Transfer Protocol (HTTP), and eXtensible Markup Language (XML).
A UPnP network consists of a Controlled Device (CD), which is a device that is connected to and controlled by an IP-based home network, and a Control Point (CP) for controlling the controlled device. The UPnP network uses a UPnP protocol stack structure that includes Internet protocols such as TCP/IP and HTTP, and technologies such as XML and Simple Object Access Protocol (SOAP), and performs communication between the control point and the controlled device through the following general steps.
In a first step (or an addressing step), a control point and a controlled device have individual IP addresses. Upon joining the network, the controlled device fetches its IP address using a Dynamic Host Configuration Protocol (DHCP), or is assigned an IP address using automatic IP addressing if there is no DHCP server in the network.
In a second step (or a discovery step), the control point searches for the controlled device, or the controlled device advertises its location. The discovery step is performed using a Simple Service Discovery Protocol (SSDP). If the controlled device is added to the network, the controlled device delivers an SSDP alive message to the network by IP multicasting, and then the control point can determine the presence/absence of the controlled device by receiving the alive message. When the control point newly joins the network, the control point multicasts an SSDP Multicast-search (M-search) message to the network, and then all of the controlled devices, which checked the M-search message, send M-search response messages containing their own information to the control point.
In a third step (or a description step), the control point checks the description content of the controlled device. When the control point wants the controlled device after checking the response message, the control point may send to the controlled device a request for detailed information related to the controlled device, and then the controlled device, which has received the request, sends its information in an XML document.
In a fourth step (or a control step), the control point operates the controlled device by controlling a function of the controlled device. When the control point intends to control an arbitrary controlled device, the control point sends a desired service to the controlled device using SOAP, based on the detailed information related to the controlled device. SOAP is a protocol that is written on HTTP by XML for the purpose of calling a remote function.
In a fifth step (or an eventing step), the control point receives a change in the event of the controlled device. The control point sends a subscribe request for a relevant event to the controlled device when the control point desires to receive an event message from the controlled device. If the subscription is successful, the controlled device sends an event message to the control point using General Event Notification Architecture (GENA).
In a sixth step or a presentation step, the control point presents a state of the controlled device using a Hyper Text Markup Language (HTML) of the controlled device.
FIG. 1 illustrates device discovery and action execution in a general UPnP network system. Referring to FIG. 1, in step 110, a control point 101 discovers or searches for a controlled device 102, or the controlled device 102 advertises its location, performing the discovery step. In step 120, the control point 101 sends an action request to the controlled device 102. In step 130, the controlled device 102 performs an action corresponding to the received action request. In step 140, the controlled device 102 responds the control point 101 with the action result. To be specific, the controlled device 102 performs the requested action, and transmits the normal execution result for the action or an error message to the control point 101.
Based on the basic UPnP control method (UPnP device architecture), a UPnP controlled device can provide various services (i.e. functions) to the control point. For example, based on the basic UPnP control method, a UPnP control point can control the UPnP controlled device in which Audio/Visual (A/V) content is stored, so that the A/V content can be replayed in another UPnP controlled device that provides a rendering service. In the case where the UPnP controlled device is a gateway, the UPnP control point can change and set an IP address band and addresses of a subnet and a gateway, to be assigned to the devices in the home, by controlling the UPnP gateway, or the controlled device.
Meanwhile, in order to perform an input operation, a general electronic device uses an input means physically mounted in the device or peripheral input devices. Therefore, the input method is restricted by the types, hardware characteristics, and performances of the electronic device or its peripheral devices. For example, a cellular phone commonly includes a keypad or a touch screen as an input means, and a TeleVision (TV) set generally has an input means such as a remote controller. Recently, interactive services such as the Internet and home shopping are being provided over the TV. Therefore, when accessing the Internet on the TV, the user must inconveniently use the function-limited remote controller in order to search the Internet over the TV.
Therefore, there is a need for a way to provide an input means that is more proper to perform an input operation, in addition to the input means that the device basically provides.